[q345]

There is a digital music player box called Squeezebox from Logitech which I have had for 5 years. The server maintains database of one's digital music (they used sqlite and also mysql). I have never had any problem for 5 years having my mp3 files on NAS. Tens of thousend of peoples maintains they collections on NAses while having database file localy, I don't recall somebody complained. ( It's an official option not a hack )

I don't know if it's a factor, but in case of Logitech Squeezebox, files are not physically get copied, which is a major differences, of course. Many other similar devices applications like amarok music player on Ubuntu, Media Monkey on Windows uses the same approach. They all have an option 'rebuild database' which scan the directory and rebuild database and those applications are by no means intended for geeks.

May be Calibre should have a similar option - rebuild database, which scan Calibre Library directory and generate metadata.db as a result. Cost of database inconsistency will be just few minutes.